EventScheduler
for dealing with deadlines.EventScheduler
to schedule an event for publication. In the example of an invoice, you would expect the invoice to be paid within thirty days. A saga would, after sending the CreateInvoiceCommand
, schedule an InvoicePaymentDeadlineExpiredEvent
to be published in 30 days. The EventScheduler
returns a ScheduleToken
after scheduling an event. This token can be used to cancel the schedule, for example when a payment of an Invoice has been received.EventScheduler
implementations:EventScheduler
uses a ScheduledExecutorService
to schedule event publication. Although the timing of this scheduler is very reliable, it is a pure in-memory implementation. Once the JVM is shut down, all schedules are lost. This makes this implementation unsuitable for long-term schedules. The SimpleEventScheduler
needs to be configured with an EventBus
and a SchedulingExecutorService
(see the static methods on the java.util.concurrent.Executors
class for helper methods).QuartzEventScheduler
is a more reliable and enterprise-worthy implementation. Using Quartz as underlying scheduling mechanism, it provides more powerful features, such as persistence, clustering and misfire management. This means event publication is guaranteed. It might be a little late, but it will be published. It needs to be configured with a Quartz Scheduler
and an EventBus
. Optionally, you may set the name of the group that Quartz jobs are scheduled in, which defaults to "AxonFramework-Events"
.AxonServerEventScheduler
uses Axon Server to schedule events for publication. As such, it is a hard requirement to use Axon Server as your Event Store solution to utilize this event scheduler. Just as the QuartzEventScheduler
, the AxonServerEventScheduler
is a reliable and enterprise-worthy implementation of the EventScheduler
interface. Creating a AxonServerEventScheduler
can be done through its builder, whose sole requirement is the AxonServerConnectionManager
.QuartzEventScheduler
and AxonServerEventScheduler
both should use the event Serializer
to serialize and deserialize the scheduled event. If the Serializer
used by the scheduler does not align with the Seralizer
used by the event store, exceptional scenarios should be expected. The Quartz implementation's Serializer
can be set by defining a different EventJobDataBinder
, whereas the Axon Server implementation allows defining the used Serializer
directly through the builder.EventScheduler
. To manage transactions on these threads, you can configure a TransactionManager
or a UnitOfWorkFactory
that creates a transaction bound unit of work.Spring ConfigurationSpring users can use theQuartzEventSchedulerFactoryBean
orSimpleEventSchedulerFactoryBean
for easier configuration. It allows you to set thePlatformTransactionManager
directly.Spring Boot users which rely on Axon Server do not have to define anything. The auto configuration will automatically create aAxonServerEventScheduler
for them.